The present invention relates to a packet communication device, and more particularly to a modular packet communication device that performs various types of routing and switching for layer 2 or higher layers of the OSI reference model in a packet exchange network.
As a packet communication device designed for function expansion, a modular packet communication device with an interface, which allows a functional module to be added later as an additional function, is known. Such modular packet communication devices are disclosed in JP-A-2003-258842, JP-A-2004-289223, and http://www.cisco.com/japanese/warp/public/3/jp/product/hs/switches/cat6500/index.shtml (Cisco Catalyst 65000). The modular packet communication device disclosed in JP-A-2003-258842 and JP-A-2004-289223 has multiple interfaces to which high efficiency processing units (functional modules) can be connected. In this module packet communication device, the transfer paths among the functional modules in the packet communication device are determined according to a manager-specified correspondence between the reception packet conditions and the processing for the packets and, based on those transfer paths, packet processing is performed by the functional modules. In addition, JP-A-2004-289223 discloses a modular packet communication device that expands the function by connecting multiple functional modules, each capable of providing the same function, and by distributing packets evenly among those functional modules for achieving processing load sharing.
In general, when a packet communication network is built, the manager sets the packet transfer method and the packet processing method (configuration definition) in the packet communication devices in the packet communication network. More specifically, the manager uses the CLI (Command Line Interface) or a commercially available management tool to send the configuration definition to the control management unit in the packet communication devices.
In a modular packet communication device, the configuration definition must be set not only in the packet communication device itself but also in the functional modules. For example, a filter rule must be set in the filtering functional module and an encryption method must be set in an encryption functional module. Such a setting content, which must be set for a function provided by a functional module, is called a requested process item. When the manager sends a configuration definition to the node control management unit in the modular packet communication device disclosed in http://www.cisco.com/japanese/warp/public/3/jp/product/hs/switches/cat6500/index.shtml (Cisco Catalyst 65000), the control management unit checks the content of each requested process item in the configuration definition to determine a functional module in which the requested process item is to be set and sets the requested process item in that functional module.
In the description below, a modular packet communication device is simply called a “packet communication device”, and the control management unit in the modular packet communication device is called a “module control management unit”.
The method used by the module control management unit to select a functional module, in which a requested process item is to be set, depends on the type of a functional module. Because of this, the method disclosed in http://www.cisco.com/japanese/warp/public/3/jp/product/hs/switches/cat6500/index.shtml (Cisco Catalyst 65000) must update the “configuration processing program”, which describes the operation of the module control management unit, each time a new functional module is developed. This update work is time-consuming and, if a bug is included in the new program, there is a possibility that the whole processing is stopped.